Pretty much just how close you two are, how much you reply to each other in the comments, how there you are for each other, and how you include each other in things like when you both did face reveals. You both have chemistry. People can see that. You two are like best friends, and some people shipped you both to be more than that. You both would shut that down quickly when it happened though, and tell other users it's not like that. It still continued for a bit afterward, but I haven’t seen it happen in a while.